A 3 pc Scale Jet-driven Outflow from Sgr A*

Abstract

The compact radio source Sgr A* is coincident with a 4 × 106 M☉ black hole at the dynamical center of the Galaxy and is surrounded by dense orbiting ionized and molecular gas. We present high-resolution radio continuum images of the central 3' and report a faint continuous linear structure centered on Sgr A* with a P.A. ∼ 60°. The extension of this feature appears to be terminated symmetrically by two linearly polarized structures at 8.4 GHz, ∼75'' from Sgr A*. A number of weak blobs of radio emission with X-ray counterparts are detected along the axis of the linear structure. The linear structure is best characterized by a mildly relativistic jet from Sgr A* with an outflow rate 10−6 M☉ yr−1. The near and far sides of the jet are interacting with orbiting ionized and molecular gas over the last 1–3 hundred years and are responsible for a 2'' hole, the "minicavity," characterized by disturbed kinematics, enhanced Fe ii/iii line emission, and diffuse X-ray gas. The estimated kinetic luminosity of the outflow is ∼1.2 × 1041 erg s−1, so the interaction with the bar may be responsible for the Galactic center X-ray flash inferred to be responsible for much of the fluorescent Fe Kα line emission from the inner 100 pc of the Galaxy.